// Copyright 2019 The gVisor Authors // // Licensed under the Apache License, Version 2.0 (the "License"); // you may not use this file except in compliance with the License. // You may obtain a copy of the License at // // https://www.apache.org/licenses/LICENSE-2.0 // // Unless required by applicable law or agreed to in writing, software // distributed under the License is distributed on an "AS IS" BASIS, // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. // See the License for the specific language governing permissions and // limitations under the License. // Server is the main gvisor.dev binary. package main import ( "flag" "fmt" "log" "net/http" "os" "regexp" "strings" ) var redirects = map[string]string{ // GitHub redirects. "/change": "https://github.com/google/gvisor", "/issue": "https://github.com/google/gvisor/issues", "/issues": "https://github.com/google/gvisor/issues", "/issue/new": "https://github.com/google/gvisor/issues/new", "/pr": "https://github.com/google/gvisor/pulls", // For links. "/faq": "/docs/user_guide/faq/", // From 2020-05-12 to 2020-06-30, the FAQ URL was uppercase. Redirect that // back to maintain any links. "/docs/user_guide/FAQ/": "/docs/user_guide/faq/", // Redirects to compatibility docs. "/c": "/docs/user_guide/compatibility/", "/c/linux/amd64": "/docs/user_guide/compatibility/linux/amd64/", // Redirect for old URLs. "/docs/user_guide/compatibility/amd64/": "/docs/user_guide/compatibility/linux/amd64/", "/docs/user_guide/compatibility/amd64": "/docs/user_guide/compatibility/linux/amd64/", "/docs/user_guide/kubernetes/": "/docs/user_guide/quick_start/kubernetes/", "/docs/user_guide/kubernetes": "/docs/user_guide/quick_start/kubernetes/", "/docs/user_guide/oci/": "/docs/user_guide/quick_start/oci/", "/docs/user_guide/oci": "/docs/user_guide/quick_start/oci/", "/docs/user_guide/docker/": "/docs/user_guide/quick_start/docker/", "/docs/user_guide/docker": "/docs/user_guide/quick_start/docker/", // Deprecated, but links continue to work. "/cl": "https://gvisor-review.googlesource.com", } var prefixHelpers = map[string]string{ "change": "https://github.com/google/gvisor/commit/%s", "issue": "https://github.com/google/gvisor/issues/%s", "issues": "https://github.com/google/gvisor/issues/%s", "pr": "https://github.com/google/gvisor/pull/%s", // Redirects to compatibility docs. "c/linux/amd64": "/docs/user_guide/compatibility/linux/amd64/#%s", // Deprecated, but links continue to work. "cl": "https://gvisor-review.googlesource.com/c/gvisor/+/%s", } var ( validID = regexp.MustCompile(`^[A-Za-z0-9-]*/?$`) goGetHTML5 = ` Go-get` ) // cronHandler wraps an http.Handler to check that the request is from the App // Engine Cron service. // See: https://cloud.google.com/appengine/docs/standard/go112/scheduling-jobs-with-cron-yaml#validating_cron_requests func cronHandler(h http.Handler) http.Handler { return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) { if r.Header.Get("X-Appengine-Cron") != "true" { http.NotFound(w, r) return } // Fallthrough. h.ServeHTTP(w, r) }) } // wrappedHandler wraps an http.Handler. // // If the query parameters include go-get=1, then we redirect to a single // static page that allows us to serve arbitrary Go packages. func wrappedHandler(h http.Handler) http.Handler { return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) { gg, ok := r.URL.Query()["go-get"] if ok && len(gg) == 1 && gg[0] == "1" { // Serve a trivial html page. w.Write([]byte(goGetHTML5)) return } // Fallthrough. h.ServeHTTP(w, r) }) } // redirectWithQuery redirects to the given target url preserving query parameters. func redirectWithQuery(w http.ResponseWriter, r *http.Request, target string) { url := target if qs := r.URL.RawQuery; qs != "" { url += "?" + qs } http.Redirect(w, r, url, http.StatusFound) } // hostRedirectHandler redirects the www. domain to the naked domain. func hostRedirectHandler(h http.Handler) http.Handler { return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) { if strings.HasPrefix(r.Host, "www.") { // Redirect to the naked domain. r.URL.Scheme = "https" // Assume https. r.URL.Host = r.Host[4:] // Remove the 'www.' http.Redirect(w, r, r.URL.String(), http.StatusMovedPermanently) return } if *projectID != "" && r.Host == *projectID+".appspot.com" && *customHost != "" { // Redirect to the custom domain. r.URL.Scheme = "https" // Assume https. r.URL.Host = *customHost http.Redirect(w, r, r.URL.String(), http.StatusMovedPermanently) return } h.ServeHTTP(w, r) }) } // prefixRedirectHandler returns a handler that redirects to the given formated url. func prefixRedirectHandler(prefix, baseURL string) http.Handler { return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) { if p := r.URL.Path; p == prefix { // Redirect /prefix/ to /prefix. http.Redirect(w, r, p[:len(p)-1], http.StatusFound) return } id := r.URL.Path[len(prefix):] if !validID.MatchString(id) { http.Error(w, "Not found", http.StatusNotFound) return } target := fmt.Sprintf(baseURL, id) redirectWithQuery(w, r, target) }) } // redirectHandler returns a handler that redirects to the given url. func redirectHandler(target string) http.Handler { return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) { redirectWithQuery(w, r, target) }) } // redirectRedirects registers redirect http handlers. func registerRedirects(mux *http.ServeMux) { if mux == nil { mux = http.DefaultServeMux } for prefix, baseURL := range prefixHelpers { p := "/" + prefix + "/" mux.Handle(p, hostRedirectHandler(wrappedHandler(prefixRedirectHandler(p, baseURL)))) } for path, redirect := range redirects { mux.Handle(path, hostRedirectHandler(wrappedHandler(redirectHandler(redirect)))) } } // registerStatic registers static file handlers func registerStatic(mux *http.ServeMux, staticDir string) { if mux == nil { mux = http.DefaultServeMux } mux.Handle("/", hostRedirectHandler(wrappedHandler(http.FileServer(http.Dir(staticDir))))) } func envFlagString(name, def string) string { if val := os.Getenv(name); val != "" { return val } return def } var ( addr = flag.String("http", envFlagString("HTTP", ":"+envFlagString("PORT", "8080")), "HTTP service address") staticDir = flag.String("static-dir", envFlagString("STATIC_DIR", "_site"), "static files directory") // Uses the standard GOOGLE_CLOUD_PROJECT environment variable set by App Engine. projectID = flag.String("project-id", envFlagString("GOOGLE_CLOUD_PROJECT", ""), "The App Engine project ID.") customHost = flag.String("custom-domain", envFlagString("CUSTOM_DOMAIN", "gvisor.dev"), "The application's custom domain.") ) func main() { flag.Parse() registerRedirects(nil) registerStatic(nil, *staticDir) log.Printf("Listening on %s...", *addr) log.Fatal(http.ListenAndServe(*addr, nil)) }